DE3200257C2 - Process for the production of artificial veneers - Google Patents

Abstract

To produce artificial veneers (11), an adhesive (2) is applied to a surface of a veneer material layer (1) which is cut from inexpensive natural wood. A layer of paint (4) is applied to a surface of a plastic release film (3), and the veneer material layer (1) and the plastic release film (3) are placed on top of one another and pressed together, with the color layer (4) facing the adhesive (2) , so that the color layer (4) is printed onto the veneer material layer (1). The separating film (3) is then peeled off so that printed veneers (7) are produced. A large number of such printed veneers (7) are combined under the action of pressure to form an artificial block of material (9), which is then split into artificial veneers (11). The artificial veneer (11) has very lifelike replicas of rings, which are represented by the color layer (4) printed on the veneer material layers (1), so that a pattern is created that comes very close to the grain of natural softwoods such as cryptomeria wood.

Description

The invention relates to a method for the production of artificial veneers according to the preamble of Patent claim 1 or claim 2. Such a method is already the subject of DE-OS 31 48 577.

If natural conifers such as Cryptomeria or the like.

are split in an oblique direction into slices in order to obtain veneers, a so-called flader-like is created Veneer picture in which ring-shaped edges in the form of flames or floral ornaments are clearly in Appearance (the corresponding split direction is referred to below as the »flat direction«, while the corresponding grain is called "Flader"). Such veneers are used for cladding well suited for interior walls. However, the occurrences of such natural woods as Cryptomeria are not sufficient so that this wood is very expensive and only limited availability.

For the production of artificial veneers, it is already known to cut an inexpensive natural wood into veneers, for example by means of a rotating peeling machine, to combine many such layers of veneer material to produce an "artificial block of material" and to cut this block of material into slices in the "flat direction" to get the artificial veneers. So is z. B. in GB-PS 13 91 077 proposed to bring a plurality of layers of veneer material stacked one on top of the other with the interposition of an adhesive between two press punches with mutually complementary curved surfaces and to press them until they are combined into a curved artificial material block, and this artificial material block in to split the »flat direction« in order to obtain artificial veneers.
In this process, the grain lines are formed by the joining surfaces between the layers of veneer material that have been joined together. If, however, the grain lines are only represented by the interfaces between the veneer material layers, this is completely insufficient to reproduce the grain of natural woods, where the grain lines appear very clearly, such as Cr>ptomeria; a replica of such a grain has not yet been successful.
The object of the invention is to create a method for the production of artificial veneers from inexpensive natural woods, whereby the artificial veneers should, however, have a grain that is very similar to that obtained from noble coniferous wood such as Cryptomeria or the like difficult to

h "> procuring untl rare woods to replace the particular very clearly appearing grain lines, the width of which is so small that they makes up about 10 to 15% of the line stocks. These

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The task is in the method of the type specified by the characterizing features of the Claim 1 or claim 2 solved.

The method according to the invention can be used to produce artificial veneers that have the veneer pattern simulate very faithfully of noble softwoods like cryptomeria. Still, they can be made inexpensive tropical woods can be obtained by using simple mass production techniques.

A simple development of the invention, in which the colored layer made of synthetic resin with corrugations is provided, enables the lifelike reproduction of the grain lines, which are in the flader-like veneer pattern of noble natural woods.

Further refinements of the invention are specified in the subclaims.

Several exemplary embodiments will now be described in more detail with reference to the drawing. In the Drawing shows

1A is a block diagram showing the individual method steps shows a first embodiment;

F i g. 1B is an enlarged partial view of an artificial one Veneer that hlocks after splitting the material is obtained in the method shown in Fig. 1A;

F i g. 2 is an explanatory illustration of essential method steps shown in FIG. 1A, wherein the steps proceed in the manner indicated by arrows;

3A shows a block diagram showing the method steps according to a further embodiment;

F i g. FIG. 3B is a schematic enlarged plan view of an artificial veneer as it is after cleaving in FIG Flat direction in the case of the FIG. 3A is obtained;

4A is a block diagram showing the method steps of a further embodiment;

F i g. 4B is a schematic enlarged plan view of an artificial veneer which is formed after a block of material has been split is held in the loading direction in the method according to Figure 4Ae.;

5A is a block diagram showing the method steps according to a further embodiment;

F i g. Fig. 5B is a schematic enlarged plan view of an artificial veneer that is formed after a block of material has been split in the loading direction in the method according to FIG. 5A is received;

F i g. Figures 6 and 7 are perspective and sectional views, respectively, of a plastic film used in another embodiment of the method; and

8 shows a partial view, shown in section, of an artificial veneer as it is according to a further embodiment of the process is obtained.

In a first embodiment of the method, a release film, on one side of which is a layer of color is applied, placed on a thin layer I of veneer material, on the surface of which an adhesive is applied so that a printed veneer is formed as a further material layer, the color layer can be annular. Reference is now made in particular to FIGS. 1A, 1B and 2. One in itself known manner cut thin layer 1 of veneer material, e.g. B. one by a rotating peeling machine manufactured wood veneer, is bleached as a pretreatment and colored with a tint (which is im hereinafter referred to as "early oiz tint"), which is very similar to the earlier natural wood (under "early Wood «is a hol / schicii, understood that between the ring areas is formed in natural wood, e.g. B. between the clearly emerging rings with Cryptomeria wood). This thin layer of veneer material I is dried, and a colorless glue 2 5 or a glue whose color is that of the early Wood is applied to a surface of the thin layer of veneer material 1.

A release film 3 made of plastic is also with a Color layer 4 provided, the shade of which (hereinafter referred to as "late wood shade") is very similar the natural latewood or summer wood (under "summer wood" that wood layer in natural wood understood which forms the ring areas, e.g. B. the clear rings in Cryptomeria wood). around a to form colored printing film 5.

Then the thin layer 1 of veneer material and the colored printing film 5 are combined with one another, the color layer 4 of the printing film 5 facing the adhesive 2 on the thin layer 1, and numerous Such layers of thin layers 1 and printing foils 5 are created in a separate manner and between flat rams 6 pressed together After removal from the press, the stack is then in the individual layer structures are broken up and the separating films 3 are peeled off. It is in this state the adhesive 2 on the fuming material layer 1 penetrated practically completely into the color layer 4, the starting point was printed by the release film 3, and the color layer 4 (in late wood tint) is on the corresponding thin layer 1 transferred to form a printed veneer 7.

Numerous printed veneers 7th, which have been formed in the manner described above, are then stacked on top of one another and, with the interposition of a stick, which is applied to the side of the thin layer 1, are introduced between paired concavo-convex press dies 8 which have mutually complementary curved press surfaces. The printed veneers 7 are then pressed together to form an artificial material block 9, which is shown in the form shown in FIG. 2 is curved. This artificial block of material 'j. is finally cut into slices by a cutting tool 10 (shown schematically in FIG. 2), specifically in the "flatbed direction". that is, in a direction shown at an angle with respect to the plane. each containing a printed veneer. In this way, finished artificial veneers 11 are finally produced.

The color layer 4, which has the "summer wood tint", is usually unstable; at the applied

however, the adhesive 2 hardens after penetrating into the paint layer 4, and consequently the paint layer 4 becomes stable and is securely applied to the thin layer 1. So if the artificial block of material 9 in the FladerrHiuJng is cut into slices, forms the layer of paint 4 clear grain lines corresponding to the wooden rings, and overall a fladrr-like one emerges Grain, the z. B. is flame-shaped and the natural grain of z. B. Very similar to Cryptomeria wood is.

Since in the embodiment described above, the paint layer is drawn in to a certain extent, an inexpensive tropical wood is preferably used for the thin layers of veneer maize rial, which has few pores, e.g. B. Wood from trees such as Agathis or Tilia japonica.

The following Tables I and II give two examples of the practical implementation of the invention Procedure.

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Table I

1. Thin layers veneer material:

a) natural wood:

Tropical wood. Agathis, 1 mm thick.

b) dyeing:

25 min in metal complex coloring solution with »early wood tinting« at 90 C.

c) Glue:

Urethane series synthetic resin (Product No. KU661 made by Japanese Corporation Konishi Co .. Ltd.). brought to an early wood tint by mixing in a brown dye.

2. Colored printing film:

a) plastic film:
Polyester film. 40 μ thickness.

b) paint layer:

3 μ thick, with nitrocellulose as a carrier and an iron-containing dye as a coloring component component.

b) Pressing pressure, time and temperature:

25 bar for 1 hour at normal temperature.

c) Total number of thin layers: 35.

4. Artificial material block:

a) Press ram: concave-convex.

b) Pressing pressure, time and temperature:

12 bar for 3 hours at normal temperature.

c) Glue:

ίο Synthetic resin of the urethane series (product no.

KU661 from Japanese Corporation Co., Ltd.) brought to an early wood tint by mixing in a brown dye.

d) Total number of thin layers: 500.
π

5.Splitting the artificial block of material:

0.6 mm thickness: gap angle corresponding to a slope of V ₂₀₀ .

3.Printed veneer:

a) Press punch: flat punch.

b) Pressing pressure, time and temperature:

22 bar for 50 min at room temperature.

c) Total number of thin layers: JO.

4. Artificial material block:

a) Press ram: concave-convex.

b) Pressing pressure, time and temperature:

10 bar for 12 h at room temperature.

c) Glue:

Epoxy series synthetic resin (product No. E250 by Japanese Corporation Konishi Co, Ltd.) by mixing in a brown Dye brought to early wood tint.

d) Gesarritanzahi of thin layers: 500.

5. Cutting the artificial block of material into slices:

0.25 mm thickness: split at an angle corresponding to a slope of 'Λοο-

Table Il

1. Veneer material of the thin layers:

a) natural wood:

Tropical wood Tilia japonica. 0.8 mm thick.

b) coloring:

For 30 min in an acid dye solution with an early wood tint at 90 ^: C.

c) Glue:

Epoxy series synthetic resin (Product No. E250 by Japanese Corporation Konishi Co, Ltd.), brought to an early wood tint by mixing in a brown dye.

2. Colored printing film:

a) plastic film:
Polypropylene film with 40μ thickness.

b) paint layer:

5μ thick, with cellulose acetate as a carrier and titanium oxide with an iron-containing dye mixed as a coloring component.

3. Printed veneers:

; ä) Press punch: flat punch.

- _> o According to the two examples above Tables I and 11 show the thin layers of veneer material. printed veneers and artificial Veneers each suitably dried to bring the water content in a range from 20 to 70% bring.

According to another embodiment, a further thin layer of veneer material with a printed veneer combined to allow variations in width between the different grain lines To reproduce natural wood of the coniferous type well. In the case of the FIGS. 3A and 3B is the production of the printed veneers 27 from thin layers coated with glue and color printing films, essentially the same as in the Embodiment according to FIGS. 1A. IB and 2. At the Embodiment now described thin layers of veneer material 21 are tinted in early wood and combined with the printed veneers 27 in a ratio of 1 to 6: 1; the printed veneers 27 and the other thin layers 21 are coated with the adhesive, and a large number of them are stacked on top of one another and then inserted between concave-convex press rams and an artificial block of material 29 compressed. This artificial block of material 29 is then split in the direction of the pile, to obtain artificial veneers 31.

In the embodiment described here, the width of the early wood can also Layer of grain can be increased by removing the

so the ratio of the additional thin layers 21 is suitably selected so that the desired masoning results, which is very similar to that of natural wood. When the conditions listed in Tables ί and II above are used, very high-quality artificial veneers 31 are created . It has been found that natural woods of the same or different types are used as thin layers to produce the printed veneers and other thin layers, and that wood without pores or with only a few pores can be used, e.g. B. Wood from trees such as Agathis or Tilia japonica, either alone or in combination with one or more different types of wood.
According to a further embodiment, the lifelike reproduction of the natural wood grain can be further improved by corrugating the printed veneers after they have been formed. As shown in FIGS. 4A and 4B are shown until the formation of the

32 OO 257

printed veneers 47 essentially the same process steps carried out, as in the embodiment according to FIGS. 1A, 1 B and 2. If the printed Veneers 47 are formed, are formed on these numerous corrugations or ridges, then the adhesive applied, and a stack of such printed veneers 47 is then between concavo-convex The ram is introduced and then pressed together to form an artificial VL> rial block 49, which is then inserted into the direction of the ornanism is split up in order to create artificial ones Obtain veneers 51.

When natural wood such as softwood, e.g. B. Cryptomeria wood, is split in the direction of the Flader, so show the The grain lines corresponding to the wooden rings usually have slight elevations. In this embodiment, elevations occur particularly on the parts which represent these grain lines, since the pattern or the corrugations of the printed veneers 47 a such grain are very similar, as shown in Figure 4B is. Using the same conditions as in Tables I and II, very high quality artificial Veneers are made.

According to a further embodiment of the invention, the width is that corresponding to the early wood Layer is enlarged, and the parts representing the grain lines are raised, so that the naturalness The replica of the natural wood grain is further enhanced by the characteristics of both Embodiments according to FIGS. 3A, 3B and 4A and 4B are used.

Reference is now made to Figures 5A and 5B. In this embodiment, too, are printed Veneers 67 are formed, as is the case with the embodiment according to FIGS. 1A, 1B and 2 already described and corrugations or numerous grooves are formed therein. Then additional thin Layers 61 of veneer material dyed in early wood tint with the corrugated printed veneers 67 combined in a ratio of 1 to 6: 1, and the printed veneers 67 and the additional thin layers 61 are provided with an adhesive. Numerous Combined veneers of this type are put together to form a stack, which is then introduced between concavo-convex press rams and an artificial one Block of material 69 is compressed. This artificial block of material 69 is then moved in the ornament direction split to obtain artificial veneers 71, the grain of which is very faithful to natural softwoods replicates. In this embodiment, too, very high quality veneers 71 are obtained by the in Tables I and II listed conditions are met.

The artificial veneers can be further optimized by the features discussed below Find application.

In the embodiments described above, those corresponding to the wooden rings appear in the grain Lines on the two sides of the artificial veneer that make up the grain lines come in handy parallel pattern lines appear, in a relatively smaller width than the grain lines in the middle zone, where they appear as a flame-shaped or flower-shaped ornament; consequently the tint appears weaker at a certain distance. According to another embodiment of the According to the invention, however, the artificial veneers receive a tint even when viewed from a distance, which gives an even impression.

IZs is shown on FIG. 6 referred to. In this execution foi-ni The strength of the late wood tint in the middle area can be different from the two side areas the color layer can be formed. In particular the middle part 84a of the paint layer 84 becomes band-shaped as a paint layer zone with a somewhat lighter shade formed as the two side regions 846. The middle area 84a of the color layer 84 lies in the form of a band the middle of a printed veneer, if this is done after the same process steps as in Fig. IA, IB and 2 is produced, so that this middle Region 84a extends as a strip along the top of a convex man-made block of material when this is made by combining a stack of printed veneers by means of concave-convex press punches will. When this artificial block of material is split, the rings correspond to the wooden rings Grain lines on the two side areas of the artificial veneer on which they are considered to be essential parallel lines in appearance ireieii, one stronger summer wood tint than the grain lines in the central area of the artificial veneer from which it is made the flame- or flower-shaped ornaments are formed: especially when viewed from a distance creates the impression of a regular tint of the entire grain of the artificial veneer.

In order to further improve this impression of regularity, according to an advantageous feature the strength of the late wood tint between the various printed veneers that make up the artificial Block of material is formed varies.

If, in the embodiments described above, a separating film made of plastic material is used for the color printing film, the separating capacity of which is very high. so there is the possibility that the paint layer is peeled off during the manufacturing process. However, when a release film is used which has poor release properties. so the printing process does not proceed satisfactorily. According to a further embodiment, a color printing film is therefore used which has both good release properties and good printing properties. In the embodiment shown in FIG. 7, a plastic film 103 is formed by combining a polyester film 103a, which is suitable with regard to the deposition of the dye and the release properties, but does not have sufficient tear strength, with a polypropylene film 1036 by means of an adhesive layer 103c such as polyethylene or urethane , which has a high tensile strength.

When using such a plastic film 103 , printed veneers can be created which hold the color layer 104 firmly on the film, while fewer difficulties arise when peeling off the color printing film.

In the embodiments described above, it can happen that the color layer on the printed veneer shines through the layers dyed in early wood tint or another layer of veneer material placed over the color layer, so that the light ring zone does not appear bright enough, especially if the thickness of the layers is less than 1 mm. A further development of the invention ensures that the bright ring zones are bright enough. It is shown on FIG. 8 referred to. A shielding layer 132 is provided over the color layer 124 on the early wood layer 121a of a printed veneer to prevent the color layer 124 from passing through the early wood layer 1216 of the overlaid printed veneer

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Veneer shows through. The shielding layer 132 is applied to the color layer 124 after the printed veneers have been formed in the same manner as in the previously described embodiments, prior to the steps of applying the adhesive and layering the veneers to form an artificial block of material. Instead of a shielding layer / 132 , to prevent the color layer 124 from showing through to the outside, an adhesive or a color can be applied to the color layer, the color of which corresponds to the early wood tint, or a metal foil is glued to the color layer.

Further modifications of the invention are possible. For example, a plastic film, which is colored tint ^r in Sommerholz- 1, z. For example, a polyester or urethane film can be used in place of the color layer applied to the plastic release liner, in association with the same plastic release liner. to be transferred onto the veneer material layer to produce a printed veneer.

The formation of undulations or grooves in the printed veneer can also take place by grooves in the pressing surfaces of the concavo-convex press die, so that an additional process step accounts for 2 ¹ S can.

For this purpose 4 sheets of drawings

40

55

bO

Claims (8)

32 OO 257 claims: 1. Process for the production of artificial veneers with a natural wood grain Flader-like grain, in which a plurality of thin layers, especially made of wood, and intermediate layers of the material of the thin layers with the interposition of an adhesive stacked one on top of the other and under pressure by means of concavo-convex pressing tools into one Block of material of the appropriate shape are combined and the block of material to the artificial veneers is cut in such a direction that the intersection lines of the merging surfaces between reproduce the flattened grain lines of the layers, characterized in that, that for each intermediate layer a thin layer in early wood tint with a layer of paint on one of them Side in late wood tint is used. 2. Verfa ^ -ςη for the production of artificial veneers with a flake-like grain simulated with a natural wood grain, in which one Multiple thin layers, especially made of wood, and intermediate layers with one in between Adhesive layered one on top of the other and under pressure by means of concavo-convex pressing tools to form one Block of material of the appropriate shape are combined and the block of material to the artificial veneers is cut in such a direction that the intersection lines of the merging surfaces between the layers simulate the flader-like grain lines, characterized in that for each intermediate layer a printing film is used, which is made of a film applied to a Trenr'Olie Color layer consists of synthetic resin in late wood tint that each printing film on the side of the Color layer using pressure with a thin layer coated with adhesive in early wood tint is connected and that the printed veneers obtained after peeling off the release film are combined to form the block of material. 3. The method according to claim 1 or 2, characterized in that at least the color layer before the stacking is provided with corrugations. 4. The method according to any one of claims 1 to 3, characterized in that the color layer consists of consists of three consecutive stripes, of which the middle one has a lighter late wood tint than the other two, laterally adjoining strips. 5. The method according to any one of claims 1 to 4, characterized in that within the block of material Layers of color in different late wood tones can be used. 6. The method according to any one of the preceding claims, characterized in that each on the color layer allows the late wood tint of this color layer to shine through through the subsequent one thin layer in early wood tint is applied through = shielding shielding layer. 7. The method according to claim 6, characterized in that that the shielding layer is formed from an adhesive. which is colored in early wood tint. 8. The method according to any one of claims 1 and 3 to 7. characterized in that the intermediate layers consist of a thin layer in early wood tint with a layer of paint on one side thereof so that a thin layer in Early wood tint is coated with an adhesive, a release film with a layer of color in late wood tint is formed on the basis of a synthetic resin, the resulting printing film with the The color layer is bonded to the adhesive layer of the thin layer with the application of pressure and the release liner is peeled off.